Transmitter.



H. S. VMATTISON.

l TRANSMITTER. APPLIQATION FILED MAB.. 22, 1909.

n Patented `Aug.16, 1910.

citizen of the United time.

HANS S. MATTISON, 0F LA GROSSE, WISCONSIN, ASSIG-NOR TO VOTE BERGER COMPANY,

OF LA. CRQSSE, WISCONSIN. i

rnansivnr'rnn.

To all whom 'it may concern:

Be it known that I, HANS iMar'risoN, a States of America, and a resident of La Crosse, county of La Crosse, and State of Wisconsin, have invented a new and useful Improvement in Transmitters, of which the following is a specification.

My invention pertains to telephone transmitters of the type having a variable resistance cell in connection with a sound receive ing diaphragm.

My improvement consists in a novel type of diaphragm, and a novel means for holding the diaphragm in place, and for insulating it from the transmitter case..

I provide a corrugated diaphragm having concentric corrugations, whereby the diaphragm is so stltfened as to eliminate its natural vibrations of the lower frequencies, and revents it from interfering with or modifying the sound waves of speech without the necessity of providing special damping springs, or other means for preventing such objectionable action. In connection with my improved type of diaphragm, I provide a clamping spring having a plurality of clamping points, which holds the diaphragm rigidly with a minimum of apparatus, and with a minimum of expense in construction. I provide also a cheap and resili ent insulating member, interposed between the diaphragm and the case, this particular form of insulating member being rendered feasible by my specific type of diaphragm.

In the drawings, Figure l shows a section on a central plane, through a transmitter, having my improvements embodied therein; Fig. 2 shows'a view from the back, with the case removed; and Fig. 3 shows the same with the bridge and terminals removed.

Like figures refer to like parts throughout the several views.

The transmitter illustrated has a plane split bridge l, clamping the body of the re sistance cell 2. A diaphragm 3 of sheet `metal is corrugated with at least. two concentric embossed rings, 'one of which ai 3 near the edge `of the diaphragm, and presents its groovesurface toward thc face plate of the transmitter case. Wit-hin Athe groove lof this corrugation is a rubber gasket 4t, to-

roidal in form, andpreferably of circular cross-section. This resilient gasket is of such size as to lie easily within the groove, and serves at the same time as a cushion and Specification of Letters Patent.

Application :tiled March 22, 1909.

`strain upon the diaphragm.

Patented Aug. 16, 1910. serial No. 484,930.

as an insulator between the diaphragm and the case; an additional corrugation 3, which may be pressed in either direction, lies between the corrugation 3 and the center of the diaphragm; more than one .such additional corrugation may be provided if desired.

A spring member, having multiple terminals, is provided for holding the diaphragm against the face plate of the transmitter, in order that it may be held in position firmly without placing the auxiliary ,diaphragm of the carbon cell under strain other than that desired in the final adjustment of parts. This spring member consists ot an annular central portion, 5, and a plurality of radial spring fingers 5. An annular insulating member 6 has a cylindrical portion and a flange, and serves to insulate the spring member from the bridge and resistance cell. The insulating member 6 is made conveniently by pressing from Very thin sheet ber, turning up the cylindrical portion as a flange, upon the annular washer. This insulating member then is retained in its place by the pressure of the spring member upon the bridge. The ends of the'springfingers are formed to embrace the rib ofthe outer corruga'tion of the diaphragm, which when Viewed from the rear appears as an annular rib which is spanned and pressed upon by the fingers. It will be seen thus that the tension of the fingers 5 is transmitted through the diaphragm and the gasket t., and then is received by the face plaie 7 of the transmitter case, without placing any My complete transmitter, therefore, presents a diaphragm free to vibrate in response to sound waves, having no natural periodicit'ies conflicting with thesound waves to be transmitted, and having no tensions other than that arbitrarily placed upon it by the iinal adjustment of the resistance cell in the transmitter bridge.

I-Iaving thus described my invention, what I claim as new and desire to .secure by United Sta-tes Letters lai ent is:

l. In a telephone transmitter, a dia` phragm having a peripheral groove in the face thereof; and a resilient gasket lying partly within said groove and between said diaphragm and the face plate of the'trans mitter case.

2. In a telephone transmitter, a circular A Within said groove and diaphragm having an annular groove in the i face thereof and a toroidal gasket lying 1.5

face thereof and atoroidal gasket lyingl partly-Within said groove and between said iaphragm and the transmitter case.

3.v In a telephone transmitter, a circular diaphragm having an annular groove in the face thereof; a toroidal gasket lying partly between said diaphragm and the transmitter case; and a spring member enga ing said diaphragm and pressing it towar the face of the trans mitter case.

4. In a telephone transmitter, a circular 'diaphragm having an annular groove in the artly Within said groove and between said iaphragm and the transmitter case; and a spring member engaging said diaphragm at a plurality of points upon the back of the diaphragm opposite vthe gasket, and pressing same toward the face of the transmitter case. Signed by meat La Crosse, county of La Crosse, and State of Wisconsin, in the presence of two Witnesses.

HANS S. MATTISON. Witnesses:

GUS. LUNDGREN, JOHN N. WALLAon. 

